Text and Data Mining valid from 2019-01-16
Received: 7 August 2018
Accepted: 6 December 2018
First Online: 16 January 2019
Compliance with ethical guidelines
: V. Feichtenschlager, F. Weihsengruber, L. Richter, I. Vujic, K. Rappersberger, and C. Posch declare that they have no competing interests.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1975 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.